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Jury Rejection of Uncontradicted Expert Testimony

August 11, 2011 in  News

New York Law Journal

We revisit a topic discussed in our column nearly nine years ago.1 That article posed a simple question: May a jury reject opinion testimony of a well-qualified expert that is not contradicted or impeached or discredited by the facts? We discussed seeming conflicts in the case law and between then-recent decisions and pattern jury instructions that routinely tell jurors they are the sole judges of the facts and of witness credibility.

Nearly a decade later there still seems to be some froth and fog enveloping this subject. Because expert testimony is at the heart of products liability litigation and medical experts routinely opine on critical issues of damages, the tension created when jurors arbitrarily disbelieve uncontradicted, unimpeached expert opinions gnaws at vital elements of the justice system. If jurors truly are empowered to reject all uncontradicted expert testimony solely on purported “credibility” grounds—let’s say, for example, the jurors simply don’t like the expert, or don’t like the way he or she dresses and, therefore, are “suspicious,” or they dislike his or her accent or speech pattern—then, how can courts be given free rein to grant summary judgment motions based on the affidavits of experts? After all, the affiant-expert may be disbelieved by the jury if forced to testify to a jury.

Similarly, if juries have unbounded discretion to discount uncontradicted, unimpeached expert testimony that is harmonious with case facts, then how can judges grant motions for new trials because the verdict was against the weight of the evidence? After all, what the clear weight of the evidence seems to be to a judge supplants the purportedly unfettered right of the jury to make a “credibility” assessment, i.e., to say, “we heard what the expert said but we simply don’t believe him.” Yet, despite pattern jury instructions about jurors having sole power to evaluate believability of witnesses, summary judgment and post-trial motion practice do not grind to a halt. The justice system credits uncontradicted, unimpeached evidence offered by the written or spoken word. This demonstrates that juror empowerment to disbelieve such proof is limited. But, then, where is the line to be drawn?

Clearly, jury instructions routinely extol supremacy of jurors in judging the facts. In New York’s Pattern Jury Instruction (PJI) 1:37, for example, the judge would tell them: “You are the sole, exclusive judges of the facts. In that field you are supreme and neither I nor anyone else may invade your province. As the sole judges of the facts, you must decide which of the witnesses you believed, what portion of their testimony you accepted, and what weight to give to it.”

Jurors are also told in PJI 1:41 that, in deciding how much weight to give to particular testimony, they may consider the interest of the witness in the outcome of the case, bias or prejudice of a witness, age, appearance, the manner in which the witness gives testimony on the stand, the witness’ opportunity to observe the facts about which he testifies, and, “the probability or improbability of the witness’ testimony when considered in the light of all other evidence in the case.” Indeed, the PJI committee comment arrestingly declares: “The jury need not accept testimony offered by a party simply because the opposing party offered no contrary testimony.”2

What does this mean? Can jurors freely disbelieve or disregard unrebutted or unimpeached testimony simply because they are allowed to apply their own tests of reliability based on their own personal experiences? Can they simply reject an expert’s testimony in a complex case, for example, when that expert is superbly qualified and his or her testimony on key points is not contradicted or impeached? New York’s PJI 1:90, a general instruction on expert witnesses, is partially illuminating. PJI 1:90 would have the judge include in the charge the following statement: “You may also reject the opinion if, after careful consideration of all the evidence in the case, expert and other, you disagree with the opinion.” This seems empowering. Can the jury simply “disagree” with the expert’s opinion?

Reasonable Justification

The comment to PJI 1:90 copiously addresses many issues regarding expert testimony, but is lean on our question. The comment says, “The weight to be accorded expert testimony is a matter for the trier of  fact.”3  Later the comment says, “The jury is not required to accept the entirety of an expert’s testimony, even where it is uncontradicted.”4 The PJI comment then offers a “but see” cite to Calderon v. Irani,5  a an Appellate Division, Third Department case in which P sued D, a gynecologist, for malpractice in causing the spread of cervical cancer by misdiagnosis. P’s expert, a gynecologic oncologist, testified that P had an 80 percent chance of long-term survival had the cancer been diagnosed earlier. This causation testimony was undisputed. Nevertheless, the jury returned a defense verdict finding that there was malpractice but that the deviation was not a substantial factor in causing the injuries.

D appealed the grant of a new trial contending that the jury was free to disregard the expert’s testimony in its entirety. The Appellate Division rejected that argument. Referring to the language of PJI 1:90, the Third Department reasoned that a jury’s rejection of an expert’s opinion “cannot be made arbitrarily, but must be based on conflicting foundational facts or opinion found in the record.” The court also noted its prior rulings that “a jury’s determination not to accept expert testimony and opinion must be supported by other testimony or by the cross-examination of the expert.”6

The court rejected D’s claim of “many discrepancies” because they either related to the expert’s opinion on failure to timely diagnose the condition, an issue on which P prevailed, or because the extent to which the expert was discredited on cross was “greatly overstate[d].” The court concluded: “Absent any reasonable justification for the jury’s rejection” of the expert’s causation testimony, the trial court was correct in setting aside the verdict.Thus, a jury’s rejection of undisputed expert testimony must have a reasonable justification.

Older case law seems to honor uncontradicted testimony when pitted against the claim of unlimited jury discretion to disbelieve it. In Chesapeake & Ohio Ry. Co.,the U.S. Supreme Court in 1931 discussed the power of a jury arbitrarily to disregard established facts. The Court recognized the “general rule” that the question of credibility of witnesses is one for the jury alone; “but this does not mean that the jury is at liberty, under the guise of passing upon the credibility of a witness to disregard his testimony, when from no reasonable point of view is it open to doubt.”

In Chesapeake, the Court found that the uncontradicted witness’ testimony disclosed “no lack of candor.” It was “not shaken by cross-examination…indeed…there was no cross-examination. Its accuracy was not controverted by proof or circumstance directly or inferentially; and, it is difficult to see why, if inaccurate, it readily could not have been shown to be so. The witness was not impeached; and there is nothing in the record which reflects unfavorably upon his credibility.” That the witness was an employee of the party was not considered a valid basis to reject the uncontradicted testimony.

The Court cited a slew of older decisions generally acknowledging the role of the jury in making credibility assessments but noted that, in many if not most of them, there were circumstances tending to cast suspicion upon the testimony or upon the witness, apart from the mere fact that he was interested in the litigation. One of the cases cited was Hull v. Litauer,9 in which the New York Court of Appeals, after acknowledging the general rule about jury assessment of credibility, stated: “Where, however, the evidence of a party is not contradicted by direct evidence, nor by any legitimate inferences from the evidence, and it is not opposed to the probabilities; nor, in its nature, surprising, or suspicious, there is no reason for denying it to conclusiveness.”10

Testimony Conclusive

In Quintana-Ruiz v. Hyundai Motor Corp.,11 the plaintiff mother sued an auto manufacturer alleging defective design when her daughter was injured upon deployment of an airbag. The jury found in favor of plaintiff and awarded damages. Defendant appealed. The U.S. Court of Appeals for the First Circuit discussed whether the jury could reject, on the ground of “bias,” the well-qualified defense experts’ powerful testimony on design of airbags. The only bias asserted was that the defendant manufacturer paid the experts’ consulting fees and that both defense experts primarily, although not exclusively, work for the defense side in such cases.12  The panel said: “A jury is not ‘at liberty, under the guise of passing on the credibility of a witness, to disregard his testimony, when from no reasonable point of view is it open to doubt.'”13 Generally, said the court, “a jury may not reject testimony that is uncontradicted and unimpeached (directly, circumstantially, or inferentially) unless credibility is at issue…. Juries, for instance, may reject uncontradicted, unimpeached testimony when it is improbable, inherently contradictory, riddled with omissions, or delivered in a manner giving rise to doubts.” But, the panel added, “[t]here must otherwise be some affirmative evidence in the record to put the witness’ credibility in doubt.”14

The First Circuit further observed that the “general rule” that a jury verdict cannot be based solely on the jury’s rejection of the other side’s uncontradicted testimony “applies with particular force to expert testimony on matters outside of lay competence.” While juries may decide what weight to give expert testimony, they are not “at liberty to disregard arbitrarily the unequivocal, uncontradicted and unimpeached testimony of an expert witness where…the testimony bears on technical questions…beyond the competence of lay determination.”15

The court further held that the mere fact that defendant paid the experts’ fees “cannot alone establish bias to overcome plausible and uncontradicted evidence that the design benefits outweighed any risks.” Thus, the defendant proffered reliable expert testimony and “the jury could not simply disregard such testimony.”

The First Circuit adhered to this approach in a later tobacco products liability case, Cruz-Vargas v. R.J. Reynolds Tobacco Co.,16 where a heavy smoker died due to hypertension which plaintiffs attributed to his habit. A jury returned a plaintiffs’ verdict. The trial court, however, granted defendant’s motion for judgment as a matter of law. One issue was whether there was common knowledge in Puerto Rico about the health hazards and habit forming nature of cigarettes. A defense expert in Caribbean social history, using competent methodology, had testified that the average consumer was aware of the health risks. The appellate court said that since the expert’s testimony was neither improbable nor contradicted, it “must be permitted to stand.” The cross-examination brought to light no contradictions undermining the expert’s testimony or information suggesting it was wrong.

Plaintiffs contended, however, that the jury was instructed to give the expert opinion “such weight as you think it deserves.” The court noted that such language is not a carte blanche for a total rejection of expert testimony. “[T]he jury could not reject the substantive, uncontradicted and unimpeached evidence upon which [Luis] Martinez’ opinion was based.” While the instruction permitted the jury, “in the event of conflicting evidence,” to reject the expert’s resolution of the conflict, “it did not allow the jury to reject the only evidence presented on the issue for no apparent reason.”17 Accordingly, judgment for defendant as a matter of law was upheld.

According to a law review case note published in 2006,18 the U.S. Court of Appeals for the Seventh Circuit, along with the Fourth and Sixth circuits, have taken a strong position that uncontradicted and unimpeached testimony is conclusive and the jury cannot disregard it simply because the jurors disbelieve interested witnesses.19 The case note posits that two other decisional “camps” exist, one in which the jury may, but is not required to, accept as true uncontradicted testimony—including in this “camp” the U.S. Court of Appeals for the Second Circuit—and the remaining “camp,” which the author refers to as the “middle ground on this issue,” namely, that juries are required to accept the uncontradicted testimony of interested witnesses, unless the witness’ credibility is in doubt or where circumstantial evidence exists to support a disbelief of the witness’ testimony.20

Such general categorizations present problems, however, and can mislead. In Powers v. Bayliner Marine Corp.,21 the products claim against a boat manufacturer alleged that defects caused the sailboat to capsize resulting in fatalities and injuries. An expert testified for plaintiff on the allegedly deficient boat design. The defense pointed to the bad weather and abundant negligent behavior as a sole proximate cause of the event. The jury was specifically instructed that it was not required to accept testimony even if was uncontradicted and the witness was not impeached. Indeed, the jury was charged that it could decide based on the “witness’ bearing and demeanor or because of the inherent improbability of his or her testimony or for other reasons you find sufficient, that such testimony is not worthy of belief.” The jury found no defect.

On appeal plaintiff argued that the jury’s rejection of its expert’s testimony regarding the sailboat’s design merited judgment as a matter of law or a new trial. The Sixth Circuit panel, in a 2-1 vote, affirmed judgment for defendant. In the course of analyzing the record, however, the court said, “[T]he jury could have rejected [the expert’s] testimony even if uncontradicted,” citing a number of cases for that proposition including one from the Seventh Circuit. Yet, the case note article referred to above had placed both the Sixth and Seventh circuits within the most stringent “camp” that held juries may not reject uncontradicted testimony. This demonstrates the need for care in making sweeping generalizations on this thorny question. The majority of the panel in Powers nevertheless affirmed the judgment for the sailboat maker because the expert’s testimony was found not to be uncontradicted.


Venerable and recent case law suggests that uncontradicted, unimpeached, unrebutted expert testimony cannot simply be ignored despite the talismanic charge that the jury is the sole judge of a witness’ credibility or the weight to be given to his or her testimony. The real question is whether the record, cross-examination, case facts, proofs and reasonable inferences genuinely offer conflicting foundational facts or opinion or real justification to reject the uncontested expert’s testimony. Obviously, there is much room here for incisive advocacy.

The jury’s rejection of an expert’s unrebutted opinion cannot be made arbitrarily. The broad instructions given to juries may inform and empower them but they do not create a legal standard by which arbitrariness, instinct and whim can rule the jury room. Similarly, such jury charges ought not be an escape hatch through which judges avoid making the hard decisions in post-trial motions or appeals.

Michael Hoenig is a member of Herzfeld & Rubin.


  1.  Hoenig, “Jury Rejection of Uncontradicted Expert Testimony,” New York Law Journal, Sept. 18, 2002, p. 3.
  2.  1A New York Pattern Jury Instructions, Civil, PJI 1:41, comment, p. 57 (3d ed. 2010).
  3.  Id., PJI, 1:90, comment, at 146-—147..
  4.  Id. at 147 (citing Preston v. Young, 239 AD2d 729, 657 NYS2d 499; Mechanick v. Conradi, 139 AD2d 857, 527 NYS2d 586; Halvorsen v. Ford Motor Co., 132 AD2d 57, 522 NYS2d 272).
  5.  745 NYS2d 610 (3d Dept. 2002).
  6. Calderon, 296 A.D. 2d 778, 745 NYS2d at 612 (citing Prescott v. LeBlanc, 247 AD2d 802, 803, 669 NYS2d 432; Baker v. Shepard, 276 AD2d 873, 875, 715 NYS2d 83; Kalfus v. Margolies, 88 AD2d 528, 450 NYS2d 189).
  7.  Calderon, 745 NYS2d at 612.
  8.  283 U.S. 209, 216—218 (1931).
  9.  162 N.Y. 569, quoted in Chesapeake, 283 U.S. at 217—219.
  10.  Quoted in Chesapeake, 283 U.S. at 218.
  11.  1303 F.3d 62, 2002 U.S. App. LEXIS 17716 (1st Cir. Aug. 27, 2002).
  12.  Quintana-Ruiz, 2002 U.S. App. LEXIS, at *33 to *44.
  13.  1Id., 2002 U.S. App. LEXIS at *35 (citing Chesapeake & O. Ry. Co. v. Martin, 283 U.S. 209, 216 (1931); Sonnentheil v. Christian Moerlein Brewing Co., 172 U.S. 401, 408 (1899); Chicago, Rock Island & Pac. Ry. Co. v. Howell, 401 F.2d 752, 754 (10th Cir. 1968)) (“The fundamental rule which makes the jury the sole judge of the weight and credibility of testimony is subject to the caveat that testimony concerning a simple fact, capable of contradiction, not incredible, and standing uncontradicted, unimpeached, or in no way discredited by cross-examination must be permitted to stand”).
  14.  Quintana-Ruiz, 2002 U.S. App. LEXIS at *37.
  15.  Id., LEXIS at *40 (citing Webster v. Offshore Food Service Inc., 434 F.2d 1191, 1193 (5th Cir. 1970); Bearman v. Prudential Ins. Co., 186 F.2d 662, 665 (10th Cir. 1951)).
  16.  348 F.3d 271 (1st Cir. 2003).
  17.  Cruz-Vargas, 348 F.3d at 278.
  18.  L. Perrone, “Judicial Takeover: Should Juries Be Required to Accept as True the Uncontradicted and Unimpeached Testimony of an Interested Party or Witness?,” 7 Florida Coastal L. Rev. 761 (Summer 2006).
  19.  Id. at 764—765 (citing Stratienko v. Cordis Corp., 429 F.3d 592, 596 (6th Cir. 2005); Sarkes Tarzian Inc. v. U.S. Trust Co. of Fla. Sav. Bank, 397 F.3d 577, 585 (7th Cir. 2005); Anderson v. Russell, 247 F.3d 125, 129—30 (4th Cir. 2001)).
  20.  Perrone, 7 Florida Coastal L. Rev. at 762—769. The Second Circuit case cited is Book v. Dettenrieder, 14 F. App’x 40, 43 (2d Cir. 2001) (unpublished opinion). In Book, however, plaintiff’s testimony was contradicted by “an ample evidentiary basis for the jury refusal to believe Book’s testimony on her pain-and-suffering for a wrist fracture.” This consisted of plaintiff’s statements to her doctor and her resumption of training and competition as an elite bicycle racer.
  21. 83 F.3d 789 (6th Cir. 1996).